Library Description

This library contains functionalities for initializing 4DotMatrix click and communication with it. Communication is done with an MCP23017 16 bit I/O expander via I2C interface. MCP23017 directly communicates with an SLx2016 display to show the characters. All the functions work in a similar fashion, in that they send a character, or several of them, to be displayed. It is possible to send single characters on any of the four display positions, a string of characters, or integers in any numeral system. C4DOT_BL_PIN should be either set to high or should be connected to a PWM module, in which case it would be possible to blink the display or change its intensity.

Key functions:

• void c4dot_init(); - Initialize the click by setting mBUS pin to appropriate logic levels.
• void c4dot_writeChar(uint8_t charNum, uint8_t charValue); - Writes charValue to the character on the position of charNum.
• c4dot_writeText(uint8_t *textToWrite); - Writes up to four characters from textToWrite to the display characters

Example description

The application is composed of three sections:

• System Initialization -  GPIO and I2C module initialization
• Application Initialization - Click driver init and setting mBus pins to appropriate logic levels
• Application Task - (code snippet) - text MikroElektronika slides from left to right and the numbers from -20 to 20 are displayed on 4 Dot Matrix click

void applicationTask()
{
 // Slide some text in from the right.
 for (i = 0; i < 21; i++)
 {
 c4dot_writeText(text + i);
 Delay_ms(150);
 }

 // Clear and delay.
 c4dot_clearDisplay();
 Delay_ms(500);

 // Write some numbers on the display.
 for (i = -20; i <= 20; i++)
 {
 c4dot_writeIntDec(i);
 Delay_ms(150);
 }

 // Clear and delay.
 c4dot_clearDisplay();
 Delay_ms(500);

}

Other MikroElektronika libraries used in the example:

• I2C

Additional notes and information

Depending on the development board you are using, you may need USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.